atsebay.t/categories.go

package main

import (
	"fmt"
	"log"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
)

func declareAPICategoriesRoutes(router *gin.RouterGroup) {
	categoriesRoutes := router.Group("/categories/:cid")
	categoriesRoutes.Use(categoryHandler)

	categoriesRoutes.GET("", func(c *gin.Context) {
		c.JSON(http.StatusOK, c.MustGet("category").(*Category))
	})
}

func declareAPIAdminCategoriesRoutes(router *gin.RouterGroup) {
	router.GET("categories", func(c *gin.Context) {
		categories, err := getCategories()
		if err != nil {
			log.Println("Unable to getCategories:", err)
			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to retrieve categories. Please try again later."})
			return
		}

		c.JSON(http.StatusOK, categories)
	})
	router.POST("categories", func(c *gin.Context) {
		var new Category
		if err := c.ShouldBindJSON(&new); err != nil {
			c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": err.Error()})
			return
		}

		if new.Promo == 0 {
			new.Promo = currentPromo
		}

		if cat, err := NewCategory(new.Label, new.Promo, new.Expand); err != nil {
			log.Println("Unable to NewCategory:", err)
			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": fmt.Sprintf("An error occurs during category creation: %s", err.Error())})
			return
		} else {
			c.JSON(http.StatusOK, cat)
		}
	})

	categoriesRoutes := router.Group("/categories/:cid")
	categoriesRoutes.Use(categoryHandler)

	categoriesRoutes.PUT("", func(c *gin.Context) {
		current := c.MustGet("category").(*Category)

		var new Category
		if err := c.ShouldBindJSON(&new); err != nil {
			c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": err.Error()})
			return
		}
		new.Id = current.Id

		if _, err := new.Update(); err != nil {
			log.Println("Unable to Update category:", err)
			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to update the given category. Please try again later."})
			return
		} else {
			c.JSON(http.StatusOK, new)
		}
	})
	categoriesRoutes.DELETE("", func(c *gin.Context) {
		current := c.MustGet("category").(*Category)

		if _, err := current.Delete(); err != nil {
			log.Println("Unable to Delete category:", err)
			c.AbortWithStatusJSON(http.StatusInternalServerError, gin.H{"errmsg": "Unable to delete the given category. Please try again later."})
			return
		} else {
			c.JSON(http.StatusOK, nil)
		}
	})
}

func categoryHandler(c *gin.Context) {
	var category *Category

	cid, err := strconv.Atoi(string(c.Param("cid")))
	if err != nil {
		c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"errmsg": "Bad category identifier."})
		return
	} else {
		category, err = getCategory(cid)
		if err != nil {
			c.AbortWithStatusJSON(http.StatusNotFound, gin.H{"errmsg": "Category not found."})
			return
		}
	}

	c.Set("category", category)

	c.Next()
}

type Category struct {
	Id     int64  `json:"id"`
	Label  string `json:"label"`
	Promo  uint   `json:"promo"`
	Expand bool   `json:"expand,omitempty"`
}

func getCategories() (categories []Category, err error) {
	if rows, errr := DBQuery("SELECT id_category, label, promo, expand FROM categories ORDER BY promo DESC, expand DESC, id_category DESC"); errr != nil {
		return nil, errr
	} else {
		defer rows.Close()

		for rows.Next() {
			var c Category
			if err = rows.Scan(&c.Id, &c.Label, &c.Promo, &c.Expand); err != nil {
				return
			}
			categories = append(categories, c)
		}
		if err = rows.Err(); err != nil {
			return
		}

		return
	}
}

func getCategory(id int) (c *Category, err error) {
	c = new(Category)
	err = DBQueryRow("SELECT id_category, label, promo, expand FROM categories WHERE id_category=?", id).Scan(&c.Id, &c.Label, &c.Promo, &c.Expand)
	return
}

func NewCategory(label string, promo uint, expand bool) (*Category, error) {
	if res, err := DBExec("INSERT INTO categories (label, promo, expand) VALUES (?, ?, ?)", label, promo, expand); err != nil {
		return nil, err
	} else if cid, err := res.LastInsertId(); err != nil {
		return nil, err
	} else {
		return &Category{cid, label, promo, expand}, nil
	}
}

func (c *Category) Update() (int64, error) {
	if res, err := DBExec("UPDATE categories SET label = ?, promo = ?, expand = ? WHERE id_category = ?", c.Label, c.Promo, c.Expand, c.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

func (c *Category) Delete() (int64, error) {
	if res, err := DBExec("DELETE FROM categories WHERE id_category = ?", c.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}